Process and apparatus for intimately contacting fluids



Aug. 1935- w. J. D. VAN bucK 2,011,186

PROCESS AND APPARATUS FOR INTIMATELY C O NTACTING FLUIDS Filed Feb. 16,1934 2 Sheets-Sheet l Aug. 13, 1935.

W. J. D. VAN DIJCK PROCESS AND APPARATUS FOR INTIMATELY CONTACTINGFLUIDS Filed Feb. 16, 1934 2 Sheets-Sheet 2 FIG. 4

lnvenbw \NJD. \lan Dijc iimz Patented Aug. 13, 1935 PATENT OFFlC PROCESSAND APPARATUS FOR INTI- MATELY CONTACTING FLUIDS I WillemJohannesDominicus van Dijck, The Hague, Netherlands Application February16, 1934, Serial No. 711,487 In the Netherlands February 11, 1933 5Claims. (Cl. 23-270) This invention relates to a process and apparatusfor bringing into intimate contact two immiscible or slightly miscibleliquids, and may in particular be applied when treating one liquid withanother in a washing or extraction process. Either liquid, or both ofthem may be replaced by a suspension or emulsion, or may consist of amixture of liquids In washing and extraction processes the com trol ofthe size of the drops in which one liquid is distributed in the other isof the utmost importance to obtahi the highest possible yield. wheninjecting one liquid into the other through openings, the size of "thedrops depends on the size of the openings and also on the velocity withwhich the passes through these opening's; this velocity .must besufficient to ensure that the jet is dispersed into approximately equaldrops and or the desired :size. If the velocity of the jet .too low, thedrops will be too large, and if it is too high, :a mixture sof'l'largeand small drops is formed.

'My invention makes it "possible to obtain in a simple manner a correctdrop Iorma'tion throughout the "whole space in which the process "takesplace by appropriate control "of the two factors mentioned above. Thismade clear by the fol- .lowing description, which is further illustratedby means of the drawingsin' whichlrliigures l and '4 :are diagrams oftwo forms of apparatus in which these principles are applied. Figures 2and 3 are details of the apparatus shown on Fig. 1. It is understoodthat the invention is not limited to the embodiments shown in Figs. 1and 4 but may be modified in any desired way in accordance with theunderlying principles.

The apparatus shown on Fig. 1 is a column designed for the treatment ofa lighter liquid with a heavier one, moving counter-currently throughthe column. The heavier, descending liquid enters the column throughline 2 and is removed through line 3, while the ascending, lighterliquid is admitted'in through line 4 and removed through line 5. Anumber of horizontal plates (1), provided with openings and consisting,for instance, of perforated sheet iron, or of metal wire gauze, arefitted and connected one tothe other by means of chains (6) Fromthebottom of the series of sheets a weight is suspended. Around theircircumference, the plates (1) are provided with rims l3 carrying, in a.groove, a packing material (M) for sealing, as shown in Fig. 2. Thesealing can also be effected irrother ways, for instance by providing aclose fit between the wall of the column and the rims of the plates,which, in order to avoid jamming, are given a rounded shape (Fig. 3).For further sealing, there are shown in Fig. 3 also spiral springs (IS)fitted in grooves. The plates (1) 5 can be moved upwards and downwardsby a reciprocating mechanism (8;). It is understood that the perforatedplates ('1) may be connected, instead of by chains, by any other means,such for example, as a central movable shaft, and the desired movementoi the system may be effected by means oi any other suitable mechanism,such as .a cam or groove The. operation of the apparatus is as follows:The lliqui'dsa'dmitted through the lines (2) and (I) now through theentire length of the column, :and :each of the "compartments formed bythe plates :(19 contains :some of each of these liquids. 'In each ofthese compartments the heavier liquidisettles toithe bottom, and thelighter ascends 20 to the top, so that there is a layer consistingsubstantially only of the heavier liquid on the upper side of eachperforated plate (1) and a layer consisting substantially only of thelighter liquid on the lower side of each plate. The flow resistance ofthe perforated plates (1) is great enough to prevent-any appreciableliquid movement through the openings in the plates owing to differencein specific gravity. Assuming that the plates begin to move upwards,while the liq- 3o uid as a whole remains practically stationary, theheavier liquid resting on top of each plate has to pass through theopenings in the plate in the form of a rain of jets which are dispersed35 as drops in the lighter liquid. The velocity 01' these jets inrelation to the absolute velocity of the plates is approximatelyproportional to the ratio between the cross-sectional area of the columnand the total area of the plate openings. 40 In this way the heavierliquid is brought into contact in a uniform fine distribution with thelighter one, and the eddy currents which are thus caused intensify stillfurther the washing between the two liquids. I 45 In the subsequent,downward movement of the plates, 9. similar process takes place on theupper side of the plates, this time however, the lighter fluid beinginjected into the heavier one. It is to be noted that on the side of aplate from which the liquid is driven to the other side, the liquidremains relatively at rest, so that there the separation of the liquidsaccording to the specific gravity can take place practicallyundisturbed, 55

and in consequence the capacity of the column is equal to that of onewithout perforated plates.

The process described repeats itself at each plate, so that an intimatecontact between the two liquids is effected over the entire length ofthe column.

The rate of movement of the perforated plates, the length of stroke, thenumber and size of the openings and the distance between the plates are,of course, determined in each particular case according tocircumstances, such as the nature and quantities of the liquids to betreated; in particular the diameter and the number of holes may vary forvarious levels in the column, so that in each stage of thewashing-process the most satisfactory size of drop is obtained. Ingeneral, it may be pointed out that in order to obtain the best possibleuniformity in the size of drops, it is better to employ small holes andapply a moderate velocity rather than large holes and a high velocity.Further, the total area of the holes in relation to the columncross-section should not be too small, as otherwise anundesirable stressis put on the driving mechanism.

Attention has already been drawn to the use of the rims (8) for sealing.Despite this sealing, however, a certain quantity of liquid always leaksthrough from one side of the plate to the other, and consequently doesnot participate in the proc-1 ess of washing, or does so onlyinsufliciently. This quantity has naturally a proportionally largervalue in columns of small diameters. In such columns, to avoid leakagelosses, the perforated plates may be permanently fixed in the column,and the liquid moved in relation to the plates as shown in Fig. 4. Inthis construction, the top and bottom of the column are each connectedby the lines it and i2, branched off from the inlet and outlet for oneof the liquids, to one of the sides of a pump 90, provided with areciprocating piston. Owing to the movement of the piston, the liquidmass in the column is given a corresponding upward and downwardmovement, and the same results are obtained as in the apparatus withmoving plates.

The apparatus (l0) represented here as a reciprocating pump, may be, ofcourse, replaced by any other device, such as, for instance, a diaphragmpump. With large washing or extraction columns the masses of liquid tobe moved according to this system are very large, and in these cases thesystem with moving plates is preferable, especially as in such cases theratio of the liquid leaking around the rims to the total amount ofliquid is relatively small.

With regard to the perforated plates it may further be pointed out that,as such, metal wire gauze with 1 mm. width of mesh has givensatisfactory results in extraction processes. It is preferable to usefor this purpose a material which is not readily wetted by the liquidsbeing contacted.

I claim as my invention:

1. In an extraction process the step of bringing into intimate contacttwo counter flowing relatively immiscible liquids of different specificgravities, by maintaining a body of fluid consisting predominantly ofthe lighter of said liquids on the lowerside of a perforated plate and abody of liquid consisting predominantly of theheavier of said liquids onthe upper side of said perforated plates, and causing said bodies tomove alternately in opposite directions through the openings in saidperforated plate.

2. An apparatus for bringing relatively immiscible fluids into intimatecontact, comprising a vessel with a pair of feed lines communicatingwith said vessel near the top and bottom, respectively, and a pair ofoutlet lines communicating with said vessel near the top and bottom,respectively, for the fluids to be contacted, a plurality of perforatedplates in said vessel disposed one above the other and transversely tothe vertical axis of said vessel and arranged to divide said vessel intoa plurality of compartments, a liquid-proof sealing means between theplates and side walls of the vessel, and reciprocating means coactingwith said apparatus to cause an oscillatory relative movement betweenthe plates and liquids in said vessel.

3. An apparatus for bringing into intimate contact relatively immiscibleliquids, comprising a vertical column provided with a pair of feed linescommunicating with said column near the top and bottom, respectively,and a pair of outlet lines communicating with said column near the topand bottom, respectively, for the liquids to be contacted, a pluralityof perforated plates arranged one above the other and within the columntransversely to its vertical axis, and adapted for vertical movement, aliquid-proof sealingmeans between the plates and side walls of thecolumn, and mechanism for imparting a vertical reciprocating motion toat least some of said plates.

4. The apparatus according to claim 3in which the perforated movableplates are suspended over each other by tension members.

5. The apparatus according to claim 3 in which the upper movableperforated plate is connected to the reciprocating mechanism by atension member, the other movable plates are suspended below said upperplates by flexible tension mem bers, and a weight is attached to thelowest movable plate.

WILLEM JOHANNES DOMDIICUS VAN DIJCK.

